Question

A two degree of freedom system comprises of two circular discs of uniform thickness keyed together with a shaft of varying dimensions (combination of circular and rectangular cylinders). The shaft is 6cm in diameter for the first 20cm of its length, 6cm × 6cm in cross section for next 30cm and 5cm in diameter for the last 40cm of its length. Calculate the natural frequency of the torsional vibrations of the shaft. Given, the masses of the disc are M1 = 400kg and M2 = 800kg and their outer diameters are D1 = 100cm and D2 = 180cm respectively. Also G = 9.0 × 1010N/m2 . Also, find the length of a torsionally equivalent shaft of diameter 6cm.

Answer 1